v3.25.4
Jointly Owned Facilities (Tables)
 12 Months Ended
Dec. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Schedule of Jointly Owned Utility Plants

At December 31, 2025, our interests in jointly-owned generating facilities and transmission systems were:

 

Ownership Interest

Plant in Service

 

Construction Work in Progress

 

Less Accumulated Depreciation

 

Total property, plant and equipment, net

 

 

 

(in millions)

 

Wyodak Plant (a)

20%

$

123.5

 

$

—

 

$

(80.1

)

$

43.4

 

Transmission Tie

35%

$

24.5

 

$

—

 

$

(8.7

)

$

15.8

 

Wygen III (b)

52%

$

144.3

 

$

0.4

 

$

(31.3

)

$

113.4

 

Wygen I (c)

76.5%

$

119.4

 

$

0.5

 

$

(64.2

)

$

55.7

 

 

(a)
In addition to supplying South Dakota Electric with coal for its share of the Wyodak Plant, our mine supplies PacifiCorp’s share of the coal under a separate long-term agreement through December 31, 2026, with an annual renewal option for one-year extensions. This coal supply agreement is collateralized by a mortgage on and a security interest in some of WRDC’s coal reserves.
(b)
South Dakota Electric retains responsibility for plant operations. WRDC supplies fuel to Wygen III for the life of the plant.
(c)
Black Hills Wyoming retains responsibility for plant operations. WRDC supplies fuel to Wygen I for the life of the plant.